Why in News:

• Using bioink made from stem cells, scientists have 3D- printed artificial corneas that mimic the human eye.

Background:

• The 3D printed human corneas were produced using bio-ink solution consisting of healthy corneal stem mixed together with alginate and collagen. The combination of alginate (a gel derived from seaweed)
• and collagen helps to keep corneal stem cells alive and produces material of necessary dimensions which is stiff enough to hold its shape and soft enough to be squeezed out nozzleof3Dprinter.